Cats love to lick. But should you be disgusted by their habit? Should you try to make them stop licking you, or even licking themselves? And if so, why is a cat’s mouth so dirty?

Are cats’ tongues clean? They aren’t. They are covered in bacteria, which will get on you if you let your cat lick you. You can keep your cat’s mouth clean by brushing its teeth or feeding it dry biscuits (which have abrasive action). But even if you do, your cat’s tongue still won’t be properly clean. If you don’t want your cat to lick you, walk away, and it will learn that you don’t want it to lick you.

The guide below is a brief one that first addresses how and why cats’ tongues are dirty. It will also cover how to keep a cat’s mouth clean, and what to do if your cat won’t stop licking you.

Are Cats’ Tongues Clean?

Cats’ tongues aren’t clean, so it’s best not to let your pet lick you. They have bacteria on them that grows because of the saliva and sugars from food in your cat’s mouth. This applies to every breed of cat, younger or older, and even still applies if you actively look after your cat’s dental health e.g. by brushing its teeth.

What makes this worse is that a cat’s tongue is rough. Bacteria, food particles and old saliva can get caught under the tiny hooks on your cat’s tongue and stay there. Bacteria can then multiply without being disturbed.

Do Cats’ Tongues Have Bacteria on Them?

Cats’ tongues have lots of bacteria on them, no matter what breed of cat you have, and no matter what age the cat is.

Bacteria can access the mouth in a number of ways. Cats can eat old food that has bacteria growing on/in it. Or, bacteria in the air could enter the mouth when the cat opens it to yawn. Once in there, there’s no way of completely getting rid of it, as even brushing the teeth can only get rid of most of it.

The older the cat is, the more bacteria its tongue is likely to have on it. That’s because older cats tend to have worse gum disease than younger ones. When bacteria gets into the gums and attacks the roots of the teeth, it isn’t easily shifted, so the overall bacterial load in the mouth is higher. So an older cat’s tongue would be dirtier than that of a kitten.

The bacteria in your cat’s mouth is what’s responsible for its bad breath.

Does a Cat’s Spit Contain Bacteria?

Spit doesn’t contain any bacteria when it’s first created. It comes from the salivary glands, which are located around the mouth. All the glands and organs in a cat’s body are sterile, as is whatever they produce, and that includes spit.

The problem is that when spit enters the mouth, it instantly becomes dirty. It picks up bacteria from the tongue, gums and teeth. And since bacteria love water, the saliva helps them multiply. According to CBC, one kind of bacteria that a cat’s mouth contains is Pasteurella multocida, which can cause infections.

If a Cat’s Mouth Is So Dirty, Why Do They Groom With Their Tongues?

Your cat doesn’t use its tongue like you might use a disposable wipe on a kitchen counter. Your cat isn’t trying to sterilize its fur (and if it were, this would be a terrible way to do it).

Rather, your cat is using its tongue like a brush. That’s why it has all those tiny hooks on it, like the tines or bristles on a brush. This pulls out any dead hairs in the coat, and wipes away any dead skin flakes or dirt. All cat species have the same kind of tongue, for the same reason.

Plus, it’s not such a big deal that your cat leaves bacteria on/in its fur anyway. Bacteria find it difficult to reproduce in conditions where there isn’t much water. While they would have something to feed on, like dead skin flakes, there’s no water so the bacteria can’t multiply. As such, the level of bacteria in your cat’s fur stays at a manageable level unless it gets wet and stays wet for a long time.

How Do Cats Keep Their Mouths Clean?

They don’t. The fact that your cat’s tongue is dirty isn’t because your cat is lazy. The only way your cat’s mouth can be made cleaner is if you clean it, or if you provide your pet with certain kinds of food.

Can You Brush a Cat’s Teeth?

You can brush a cat’s teeth, and in an ideal world, you should. But it’s not easy to train a cat to let you do it.

According to the Journal of Nutrition, cats can experience many kinds of dental disease like plaque, gingivitis, and periodontal disease. PD is characterized by inflammation in the gums. But all of these issues can be avoided:

Gingivitis can be prevented or reduced by the regular removal of plaque from the tooth surfaces by, for example, meticulous and frequent tooth brushing using a veterinary toothpaste and toothbrush. … Toothbrushing reduced gingivitis on the buccal tooth surface to some degree, although the effect was not as marked as anticipated.

However, they also note that ‘it is very difficult to toothbrush cats’ teeth and therefore the toothbrushing may not have been effective enough to reduce the degree of gingivitis to a low level.’ It’s for this reason that few owners brush their cats’ teeth despite the fact it may be helpful.

How Do Cats Keep Their Mouths Clean?

In short, cats don’t keep their mouths clean. As stated above, your cat’s mouth is full of bacteria. But what’s more, your cat won’t do anything to prevent that. Even if it wanted to, there’s precious little it could do.

What does make this less of an issue is that your cat only has long, sharp teeth. It doesn’t have teeth that things can easily get stuck between like we do.

What you can do for your cat, though, is feed it dry food. This doesn’t have to be a permanent switch, because cats which eat nothing but dry food often develop kidney problems. But the rough and abrasive cat biscuits can have a slight cleaning effect on your cat’s teeth. According to the journal Animals, ‘the explanation for this fact stays with the abrasive properties of dry food, capable of removing the teeth plaque.’ What’s more, dry food can help clean the mouth in other ways:

Dry food can eventually be responsible for an increased production of saliva. It is well known that saliva contains immunoglobulins produced in reaction to the antigens found in the mouth, and, therefore, dry food eventually will also be responsible for a better use of the immune system in the prevention of oral health issues.

This means that if you feed your cat at least some dry food, its dental health should be improved, and its saliva/tongue should be cleaner. They won’t be germ-free, as even tooth brushing wouldn’t be that effective. But this is better than nothing.

Can You Let a Cat Lick You?

You can let your cat lick you if you want, so long as you’re aware of what that entails. Your cat’s tongue and spit contain lots of bacteria, and it’s best if you wash this off your skin after your cat licks you.

Will a Cat Licking You Give You an Infection?

Letting your cat lick you could give you an infection. Infections occur when bacteria enters a wound or a membrane. Once inside, it can proliferate. It will cause swelling, pain and redness. Your cat could give you an infection:

• In an open wound. A bite wound, a scratch mark or a graze can become infected. Bacteria can feed on dead cells, e.g. skin cells. If your cat licked a wound on your skin then it would become infected if not washed.
• In your eye (i.e. pinkeye). Pinkeye is a form of infection where bacteria enters the membrane around the eye. This can happen if your cat licks your face.

You can also transfer bacteria from one place to another. If your cat licks your fingers and you rub your eye without washing your hands first, you could catch pinkeye that way instead.

Why Do Cats Lick Their Owners?

Cats may lick their owners as a way of building a bond.

When a cat gives birth to kittens, it has to provide every aspect of their care. That means keeping them safe, feeding them and grooming them. To groom a kitten, a cat will lick it, just like how it grooms itself. It’s possible that your cat is licking you as if to show affection.

That’s not the only option, though. It could be that your cat tastes something interesting on your skin: something you ate earlier, for example, or maybe your sweat. Or, it might be that your cat just wants your attention.

What all of these possibilities have in common is that they’re sweet. While the precise reason your cat licks you may not be clear, it’s definitely not that your cat hates you, wants to eat you, or wants to get away from you. You may therefore not want to make your cat stop licking you, and that’s fine—so long as you wash your hands afterwards!

How to Stop a Cat Licking You

The best way to get a cat to stop licking you is to gently encourage it to try a different behavior.

One way of doing this is to apply something bitter-tasting to your skin wherever your cat typically licks (e.g. your fingers). When your cat next licks your fingers, it won’t enjoy the way they taste, and should learn not to do that again. The problem is if your cat then associates that negative feeling with you generally. That would make your cat dislike you, which is bad.

A better way is to deal with the behavior by redirecting it. If your cat likes to lick your face, then move your face away. Your cat may lick your arm, but that’s at least less of a problem for you than having it lick your face.

If nothing else works, then whenever your cat licks you, walk away and leave it alone for a while. It will learn that its behavior of licking makes you leave, which it presumably doesn’t want. It will then learn to stop.